1. Field of the Invention
This invention relates generally to electric switches and more particularly to switches for lockably receiving user inserted dual-function elements which serve as wire terminals for coupling the switch into an electric circuit and provide the internal switching contacts of the switch.
2. Description of the Prior Art
A considerable variety of electric switch configurations have been devised for general purpose and special applications, and although these prior art switches vary in structural details, they usually include the same basic elements. Briefly, these switches have a dielectric switch case with a switch actuator, or toggle mechanism, mounted therein for pivotable movement into and out of electrically conductive engagement with metallic elements provided within the switch case. The metallic elements, which are riveted, crimped, or otherwise fixedly embedded in the switch case, are configured with internally disposed contact portions and have integral lugs which protrude from the switch case to provide external means for attachment of circuit wires to the switch.
This briefly described basic switch design is shown and more fully described in the following U.S. patents which are exemplary of the prior art. U.S. Pat. Nos. 3,158,704, 3,701,870, 4,101,479 and 4,268,734.
Although these particular prior art switches, and the large variety of similar switches, have proven satisfactory over the years, they have some shortcomings with regard to costs, reliability and ease of installation.
The manufacturing costs of these prior art switches are effected by the costs of the metallic elements per se and the assembly time needed to fixedly embed those elements in the switch casings.
As is known in the art, each mechanical junction in an electric circuit increases the electric resistance of the circuit and also increases the chances of circuit failure due to corrosion build up and the like. In the prior art switches, a minimum of two, and sometimes three mechanical junctions are required for each circuit wire that is connected to the switch. In some instances, bare wires are soldered, or otherwise attached directly to the extending lug portions of the switch's metallic elements and in such cases, two mechanical junctions are employed for each wire connection, namely, that used to connect the bare wire to the exposed lug, and the internal contact made within the switch case when it is opened and closed. In other, and more commonly used instances, the bared circuit wires are suitably joined to wire terminals which are in turn attached, such as with screw connections, frictional interconnection or the like, to the exposed lugs of the switch's metallic elements. Thus, in these latter cases, three mechanical junctions are used for each wire connection. Namely, the junction where the bared wire is connected to the wire terminal, the junction of the wire terminal to the exposed lug of the switch's metallic element, and the internal contact made within the switch case when it is operated.
With regard to prior art switch installation, in many instances, switches are mounted in areas where access to the back of the mounting panels is limited at best. In such situations, the otherwise relatively simple act of attaching circuit wires to the exposed lugs of the switch's metallic elements can be a frustrating task.
Therefore, a need exists for a new and improved electric switch which overcomes some of the shortcomings of the prior art.